As illustrated in FIG. 8, a magneto-optical disk device, as one of the magnetic disk devices provided with a floating-type magnetic head, has a floating-type magnetic head 3 and an optical head 7 which are disposed opposite to each other with a magneto-optical disk 4 situated in between, and a motor 5 for rotating the magneto-optical disk 4. The floating-type magnetic head 3 is provided with a miniaturized magnetic head 1 fixed to a floating slider 2 that is supported by a suspension 6, and adapted to float above the magneto-optical disk 4 with a substantially constant floating height of several .mu.m to several tens .mu.m as the magneto-optical disk 4 rotates. The floating height is determined by a balance between an upward lift caused by air flowing between the magneto-optical disk 4 and the floating slider 2 and a downward depressing force by the suspension 6. In addition, the magneto-optical disk 4 includes, for example, a substrate 4a, a recording layer 4b having a vertically magnetized film and a protection layer 4c.
With the floating-type magnetic head 3 floating above the magneto-optical disk 4, a light beam from the optical head 7 is converged on the recording layer 4b to cause a temperature rise. On the other hand, a magnetic field driving current is supplied to the magnetic head 1 by a driver circuit 8, and thus a magnetic field alternately changing its direction between upward and downward (which directions are perpendicular to the recording surface of the magneto-optical disk 4) is applied to the magneto-optical disk 4. Consequently, new information can be recorded by an overwriting operation of the magnetic field modulation recording method which obviates the necessity of erasing operations for already recorded information.
Meantime, for commonly used magneto-optical disk devices, so-called contact start/stop method (hereinafter, referred to simply as CS/S method) is adopted in the floating operation of the floating-type magnetic head 3. According to the CS/S method, the floating slider 2 is in contact with the surface of the magneto-optical disk 4 during stopping of the rotation of the magneto-optical disk 4, and upon starting of the rotation of the magneto-optical disk 4, the floating slider 2 starts sliding on the magneto-optical disk 4 to float. When the rotation of the magneto-optical disk 4 is stopped, the floating slider 2 slides on the magneto-optical disk 4 to return to the contact state with the magneto-optical disk 4.
Here, in order to protect the recording layer 4b from damage due to friction caused when the floating slider 2 slides on the protection layer 4c, our Japanese Unexamined Patent Application (see Tokuganhei 1-288321) teaches a magneto-optical disk device wherein a sliding area for the floating slider 2 is provided in a predetermined area not having the recording layer 4b.
In this case, after forming a protection layer 4c, it is preferable to apply a lubricant to the protection layer 4c in order to reduce friction between the floating-type magnetic head 3 and the protection layer 4c.
However, in the above arrangement, the repetitive sliding operations of the floating slider 2 cause the lubricant to be consumed or removed from the sliding area because of friction between the floating slider 2 and the lubricant. This results in such a drawback that the floating slider 2 may stick to the sliding area or the magnetic head 1 may be damaged.
FIG. 9 schematically illustrates a surface condition of the sliding area whereon 30,000 times of the sliding operations have been performed by the floating slider 2. In FIG. 9, there remains sufficient lubricant in areas A; only a little lubricant in areas B; and almost no lubricant in areas C. On the other hand, FIG. 10 schematically illustrates a surface condition of the floating slider 2 with respect to the area opposite to the sliding area after having performed 30,000 times of the sliding operations. There is lubricant, removed from the sliding area, adhering to an area D indicated by hatching. Especially, there is a lot of lubricant adhering to side edge portions that are parallel to the lengthwise direction of the floating slider 2. These side edge portions correspond to the areas C in FIG. 9, having almost no lubricant.
As described above, in the arrangement of the magneto-optical disk device for permitting the sliding operation of the floating slider 2 to be performed on the sliding area provided outside the recording area, although damage of the recording layer 4b can be sufficiently reduced, problems such as sticking of the floating slider 2 and damage of the magnetic head 1 still remain unsolved.